1. Field of the Invention
The present invention relates to a charging and discharging control apparatus that controls the charging and discharging of an energy storage device, and to a method for controlling the charging and discharging of an energy storage device.
Priority is claimed on Japanese Patent Application No. 2003-143405, filed May 21, 2003, the contents of which are incorporated herein by reference.
2. Description of Related Art
Conventionally, in vehicles that run using an electric motor such as electric vehicles (EV) and hybrid electric vehicles (HEV), there are cases in which, depending on the running state of the vehicle, the power required cannot be obtained from an energy storage device such as a battery or capacitor mounted in the vehicle. Because of this, an apparatus is used that controls the discharging power and charging power (i.e., the regenerative power) such that the terminal voltage of the energy storage device does not rise above a maximum allowable voltage or drop below a discharge final voltage.
Specifically, this apparatus measures voltage between terminals of an energy storage device that is mounted in a vehicle, and if this voltage drops below a reference voltage amends the maximum discharge power using a restriction coefficient so as to limit the output of power output from the energy storage apparatus. On the other hand, if the voltage between terminals of the energy storage device rises above a reference voltage, the apparatus corrects the maximum charging power using a restriction coefficient so as to limit the charging power that is input into the energy storage device (see, for example, Japanese Patent Application Unexamined Publication No. 09-215111 (paragraph 0031 and FIG. 17) and No. 09-312901 (paragraph 0034 and FIG. 21).